1. Field of the Invention
The present invention relates to ladder copolymers in which one of two backbones (legs or sides of a ladder) is formed of a nucleic acid or nucleic acid-like polymer.
2. Description of the Related Art
During the past half-century the known functions of nucleic acids have expanded from genetic information carriers and messengers to include catalysis and regulation of a number of cellular processes. In addition, many nucleic acid-based structures have been developed with medicinal applications, catalytic properties, and prebiotic chemistry implications (Pearson, 2003; Dennis, 2002; Couzin, 2002). Notable examples are antisense agents (Uhlmann et al., 1990), e.g., peptide nucleic acid (PNA)(Nielsen, 1999), deoxynucleic guanidine (DNG) (Barawkar et al., 1999), and locked DNA (LNA) (Vester et al., 2002; Demidov, 2003). DNAzymes have been developed with functionalized nucleotidyl groups to enhance catalytic abilities (Santoro et al., 2000; Thum et al., 2001; Lermer et al., 2002). TNA, (3′,2′)-α-L-threose nucleic acid, has been suggested as an evolutionary progenitor of RNA and/or DNA (Schoning et al., 2000; Chaput et al., 2003).
A goal of the present inventors is to develop new nucleic acid-based materials to expand the applications and scope of DNA nanotechnology (Seeman, 1999). A number of topological targets, objects, devices, and 2D arrays have been prepared from conventional DNA molecules with defined sequences and unusual structural motifs (Seeman, 2003; U.S. Pat. No. 5,386,020; U.S. Pat. No. 6,072,044; U.S. Pat. No. 6,255,469). Analogous DNA/organic polymer conjugates of these structures offer practical interest. For example, DNA 2D arrays (Winfree et al., 1998) may serve as platforms to assemble molecular electronic devices with nanometer precision, or as templates to synthesize non-DNA polymeric 2D networks that would enjoy the stability and other favorable properties of organic materials. Single-stranded DNA has been used to direct polymerization of DNA oligos with unnatural linkages (Li et al., 2002; Schmidt et al., 1997; Seitz et al., 2001). An object of the present invention is to harness the full power of DNA nanotechnology, which depends on both secondary and tertiary DNA structural motifs, to assemble organic materials with unique structures, and the approach of the present inventors also entails regio-specific chemistry between non-DNA entities.
Citation of any document herein is not intended as an admission that such document is pertinent prior art, or considered material to the patentability of any claim of the present application. Any statement as to content or a date of any document is based on the information available to applicant at the time of filing and does not constitute an admission as to the correctness of such a statement.